A safety interlock system for hand operated vehicle accelerator control systems is disclosed which permits a hand operated accelerator control system to be immobilized so that it cannot be activated unintentionally or accidentally by an individual operator who is not familiar with a vehicle so equipped. The safety interlock system may be selectively activated by the vehicle operator manually directly by mechanical means or remotely by means of a switch-controlled hydraulic, pneumatic or electrical activator. An indicator system is provided which indicates the status of the safety interlock system to the vehicle operator.